The study investigates the mechanism behind acute leukopenia, specifically granulocytopenia and monocytopenia, observed in patients during the first hour of hemodialysis using cellophane-membrane equipment. The research demonstrates that complement activation occurs when plasma is exposed to dialyzer cellophane, leading to the entrapment of granulocytes and monocytes in the pulmonary vasculature. This activation is primarily through the alternative pathway of complement activation, as evidenced by the conversion of C3 and factor B in plasma. In vitro experiments with human plasma show that cellophane incubation results in a significant decrease in total hemolytic complement, particularly C3, while C1 levels remain stable. The activated complement components, likely with a molecular weight of 7,000-20,000 daltons, induce granulocyte chemotaxis and adhesion, contributing to the leukostasis observed in patients. Rabbit studies further证实了这些发现，表明激活的补体成分在肺部导致粒细胞和单核细胞的聚集。此外，研究还探讨了补体激活对粒细胞功能的影响，以及补体激活在其他临床情况下的潜在作用，如慢性粒细胞减少症。The study investigates the mechanism behind acute leukopenia, specifically granulocytopenia and monocytopenia, observed in patients during the first hour of hemodialysis using cellophane-membrane equipment. The research demonstrates that complement activation occurs when plasma is exposed to dialyzer cellophane, leading to the entrapment of granulocytes and monocytes in the pulmonary vasculature. This activation is primarily through the alternative pathway of complement activation, as evidenced by the conversion of C3 and factor B in plasma. In vitro experiments with human plasma show that cellophane incubation results in a significant decrease in total hemolytic complement, particularly C3, while C1 levels remain stable. The activated complement components, likely with a molecular weight of 7,000-20,000 daltons, induce granulocyte chemotaxis and adhesion, contributing to the leukostasis observed in patients. Rabbit studies further证实了这些发现，表明激活的补体成分在肺部导致粒细胞和单核细胞的聚集。此外，研究还探讨了补体激活对粒细胞功能的影响，以及补体激活在其他临床情况下的潜在作用，如慢性粒细胞减少症。